1. Field of the Invention
This disclosure relates generally to light field otoscopes.
2. Description of Related Art
An otoscope is an optical imaging device used to view and diagnose disease in the middle ear. Clinicians use image features such as color, translucency, and three-dimensional (3D) shape of the tympanic membrane (TM) for diagnosis. Traditional otoscopes severely limit the field-of-view (FOV) and magnification of the TM. This creates monocular tunnel vision for the user, which reduces the ability to assess slight differences in shape and color. New digital otoscopes can provide high-resolution large FOV images, but their current imaging sensors do not provide quantitative measurements of 3D shape or color.
Compared to a traditional imaging sensor, a light field imaging sensor uses a microlens array to record the complete four-dimensional (4D) ray space. Light field data can be used to reconstruct multiple views of a scene, with each view having different perspective. These views can then be further post-processed to reconstruct 3D shape. However, the accuracy of the 3D reconstruction is dependent on many parameters of the optical system, such as the numerical aperture (NA), magnification, pixel pitch, and microlens pitch. Optics used in current otoscopes and otoscopes have parameters that result in low-accuracy light field 3D reconstructions.
Light field imaging sensors can also enable a modality called “multispectral imaging.” Spectral images can be encoded into reconstructed views by placing optical filters in the aperture plane. Current optics within otoscopes and otoscopes contain very small and/or inaccessible apertures, which makes insertion of spectral filters impractical.
Therefore, there is a need for a new type of optical system designed for 3D and spectral measurement in otoscopy.